My 74 2.0 with dual Dell 40s seems to run best at the following timing advances -

13 Degrees at 900 Idle RPM
37 Degrees at 3500 RPM

Are these numbers reasonable for a carbed 2.0L ? I do not know if the previous owner changed the cam when the fuel injection system was removed. I would be interested in hearing what others are running for advance with similar setups.

Thanks all,

Ansbacher

37 deg at 3500 is reasonable.

What is your compression ratio, what gas do you run?
What distributor do you have?

I have never pulled the dizzy, and cannot see the label in the position it is in, so don't know what it is. Don't know my compression ratio. I run non-ethanol 89 octane gas.

In my opinion 37 degrees of advance on a stock motor is a bad idea.
27, maybe as high as 30 would be as far as I would go, ever ever.

The car will not run at 27 degrees. A while back I started a thread questioning the validity of my timing marks on my fan for that very reason. Then I read a lot of references that stated carbureted 914s need a much higher advance than a stock car with FI. Listening to both sides of this issue has me worried again. My temp gauge does not exceed much past the halfway point, even on a hot day here in Florida, so I kinda figured I was not advanced too drastically. Wish I could get a handle on this.

Ansbacher

I recall that thread, but did you ever remove the fan and properly mark it?

No. It seems to have the factory white and red marks in the proper places, and everyone said the fan could not be mounted in the wrong orientation, so I am assuming the marks are good.

How do you know you are at 37 degrees advance?
Is the fan marked or are you using a gun that can read it and display it?

If it's the gun, I would get an old school one with no adjustment and test it again.

I have both types of timing guns. The dial-in type tells me I am at 37 degrees using the white TDC mark and the oild school one shows I am approx. 10 degrees beyond the red 27 degree mark- voila 37 degrees.

Ansbacher

That seems like way too much.

Forget the marks and time it with a vacuum gauge. Connect the gauge to the engine and set the timing for maximum vacuum at idle.

That's how we did it in the old days when timing marks were gone. An "inches of Water" gauge is best for this.

Afraid measuring timing with a vacuum gauge is Greek to me. Would not know where to begin. Sure wish other owners of carbureted cars would chime in with their advance numbers, so we could get a consensus on this. Anyone...???...

Ansbacher

Mine is set to 34 degrees and I have some room left to give it a little more.

I run pump gas (91) with 9.5:1 CR, 1 mile high with a Mallory Unilte Dist. & MSD.

34-37 degrees @3500 is what many of the vintage guys are running.
Lower altitude (more air) and you should back that off a bit.

Stugray - Your numbers are encouraging. Question...if you set your car to 27 degrees (red mark) would it stumble all over itself and barely run?


Ansbacher

Connect gauge to vacuum source.

Loosen distributor clamp.

start engine.

turn distributor (back/forth) until maximum vacuum is read on the gauge.

tighten distributor clamp.

disconnect vacuum gauge.

Go drive.

Easy!

Thanks Mike, you have taught me something. Can't wait to try it.

Ansbacher

Vintage guys, and Stu are using higher compression motors....
Possibly different Camshafts.

You, setting your timing that far advanced, have created a potential of running too lean and buring up a piston, or buring a valve.

Rich

Ah, timing............ one of those things I haven't even thought about yet, but need to.

When I rebuilt my motor, I was thinking enough to paint the mark red when I restored the fan, and cleaned up the timing notch but that's it. I assumed I would set the engine at true TDC, maybe break out the protractor to set close to the 27 BTDC. Then break the engine in, then set the timing at 27 BTDC at 3500 RPM with a timing light, then sync carbs, set mixtures, set timing again, etc.

I figured when I bought a light, it would be one with a tach and that you can advance or change the light timing to keep the notch and line. i.e. set the light for 0 and when you move the distributor to line up the timing mark you will be at 27 BTDC. Want to go 30 BTDC, set the timing light with a +3, want to go to 24 set the light to -3. Does this make sense, or do I have too many damaged brain cells? (I only had 2 Guinness to celebrate my ancestry yesterday)

Granted, I haven't set the timing on a car since......... well, you don't want to know but it is at least 20 years...... Reading this, I realized that I may be wrong in my assumptions

I am running Dells, and a Pertronix Billet Distributor.

With a variable timing light, I set it at 34 degrees
Then I use the TDC mark on the flywheel and not the oneS on the fan.

Not sure this is doable on a 912E. Any reason you do it this way as opposed to off the fan?

Is my assumption that setting the light for '0' advance and aligning the mark will put me at the correct 27? I'm sure that with all the modifications, bigger cam, hotter spark, mechanical advance, carbs bump in displacement and compression the timing needs will change, but am just looking for a starting point.

Thanks!

That is a good starting point for you.
To get your car setup really well, you need some sensors to monitor heat, mixture etc....
EGT and AF, along with head temp would be the ones I would implement.

You dont "need" a dyno to do it, but it will help alot to see what changes will do for your specific non stock motor.
Seat of the pants/Iphone dyno and the right sensors will get you darn close in my experience, but if you are searching for every bit of HP, a dyno is a good tool.

Rich

If you are not having issues( heating , pinging etc) why worry

I'd say, since all the other ways are not giving you accurate readings, try doing some driving and pull the plugs and take a look at them?

Does your distributor have a vacuum advance on it?


Robert

[/quote]
That is a good starting point for you.
To get your car setup really well, you need some sensors to monitor heat, mixture etc....
EGT and AF, along with head temp would be the ones I would implement.

You dont "need" a dyno to do it, but it will help alot to see what changes will do for your specific non stock motor.
Seat of the pants/Iphone dyno and the right sensors will get you darn close in my experience, but if you are searching for every bit of HP, a dyno is a good tool.

Rich
[/quote]

Yes, planning AF using the PLX and CHT. Because I am a total neub with this motor, and have done a complete rebuild, with several mods, I will likely take it to a shop for a final tune and dyno before I start daily driving it. Will likely do this when I get out to the PNW.

Timing with carbs

http://www.pelicanparts.com/techarticles/9...iming_carbs.htm

Well, you all scared me into backing off on my timing. With a lot of patience I have got it running remarkably well at 34 degrees at 3500 RPM (was at 37 degrees), but that seems to be the limit. Anything lower makes it feel like a tractor.

Ansbacher

Ansbacher, does your have vacuum advance or mechanical only? Im trying to sort out the same problem. I have twin 40 IDFs and 009 distributor ( mechanical advance) Unfortunatly, I have no idea what cam, compression ratio, or even displacement the engine has. The timing right now is something like 20 BTDC at idle. It shoots right past the red mark at higher RPMs. I guess I better dial it back some and see if it still runs ok.

Nick

NFBrown - I do not have a vacuum advance, just mechanical. If you have 20 degrees at idle I would imagine you are dangerously at or beyond 40 degrees at high RPM. For me to get 34 degrees, I am at about 10-12 degrees at idle. By all means, back it off!

Ansbacher

too much advance will NOT make the engine run lean, it WILL make it susceptible to preignition [ping].

to get close you can run the engine up to 3500 rpm and while watching the tach turn the distributor to get the highest rpm and then back it off a bit, then go out and test drive it listening for preignition. back it off until you don't hear any at high load.

do all this with the engine up to temp.

this is suggested because you state that you are unsure of your timing marks, you can them compare where this got you on the timing that you had.

What distributor do you have on your stock motor that does not have vacuum advance?

Rich

Let's agree to disagree on this fact.

A motor that is running too rich will require quite a bit of advance to run even close to right, it's moving the timing of the event of combustion to a point during the intake cycle where there is less fuel (leaner) to allow it to fire at all....

So, too much advance on a properly setup motor will indeed make it run lean, it's simple timing.

In this case, I suspect that he may have a fuel issue and is currently running way to Rich with no method to test it or meter it.
With a stock motor running 37 degrees of advance, he is so rich the car won't run and won't idle without a significant amount of advance to attempt to get back to a burn able mixture.

He needs to tune down the fuel, and retard the timing back to normal at 27 degrees advance.

Could be carbs, could be too much fuel pressure, could be the DJET is tuned wrong....any or all of it.
The way it is setup now, the motor will not last long with that much advance.

true, he hasn't mentioned that his eyes are burning with it idling so i didn't assume that his carbs were over jetted.

It is much easier to aim gun and see flywheel mark instead of aiming through fan housing on a 914.

Ansbacher, just remove the 13mm nut from distributor clamp, pop off the cap, pull distributor and read the part number and pop it back in. Took me longer to type than to it takes to do it.

I use a Mallory Unilite. 12 degrees initial 28 full advance. I'm at 9.5:1 and run 93 octane.

I suspect my carbs are jetted too rich. I have not reset the timing; it was like this when I bought the car. I'm going to retard it as much as I can and still have it run. Then look at rejetting and an SVDA distributor to replace the 009.

Nick